Refrigerator Having a Disbursed Cooling Air Stream Directed Upwardly From a Pressurized Plenum

ABSTRACT

In a refrigerator, warm air is collected or drawn into a warm air return duct opening located at or near the top of the refrigerated space instead of the bottom. The warm air is passed through an evaporator where it cools. The cooled air is driven into a pressurized plenum located at the bottom of the refrigerated space. The plenum is defined by a screen extending across the bottom of the refrigerated space. Air in the plenum passes through holes in the screen and driven upward. The air flow inside the refrigerator is thus upwardly, i.e., from the bottom to the top.

BACKGROUND

Prior art refrigerators typically introduce cold air at the top of a cabinet through a cold-air supply duct. They also typically draw in or “intake” warm air at the bottom of the cabinet through a “return” air duct. Locating a cold air supply duct at the top of a refrigerator cabinet takes advantage of the fact that cold air, being denser that warm air, falls downwardly, however, in some instances, locating the cold air supply duct at the top of a refrigerated cabinet can provide a less than optimum air flow distribution. The temperature inside the refrigerator at different elevations and different horizontal locations can be uneven if the refrigerated air introduced at the top of a cabinet is able to find an unobstructed path to the warm air return.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is perspective view of a refrigerator;

FIG. 2 is a side view of a refrigerator, including the ones depicted in FIG. 1 and FIG. 2, and depicting an upwardly-directed cold air flow;

FIG. 3 is a perspective view of a refrigerator showing an inclined screen, which defines a converging duct, and which is perforated;

FIG. 4 is a front view of the refrigerator depicted in FIG. 3;

FIG. 5A is a side view of the refrigerator depicted in FIGS. 4 and 5;

FIG. 5B depicts an air profile;

FIG. 6 is an isolated view of a portion of the inclined screen portion and depicting how the thickness of the screen can affect air flow through the screen;

FIG. 7 is a perspective view of a refrigerator and having an alternate embodiment of an inclined screen that defines a converging duct portion and that provides a different air flow profile than the screen shown in FIGS. 3-6;

FIG. 8 is a front view of the refrigerator depicted in FIG. 7; and

FIG. 9 is side view of the refrigerator depicted in FIGS. 8 and 9.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of a refrigerator 100. The refrigerator 100 is comprised of a cabinet defined by a top 102, a bottom 104 not visible in FIG. 1, a left side 106, a right side 108 not visible in FIG. 1 and a front door 110.

FIG. 2 is a cross-sectional view of the refrigerator 100 shown in FIGS. 1 and 2.

The refrigerator 100 has an interior space or volume 200 defined by the left side 106 and the right side 108 (shown in FIG. 1 and FIG. 2), a rear side 112, the top 102, the bottom 104, and the door 110. Warm air is depicted in FIG. 2 by arrows 202, which are drawn pointing upwardly and into a warm air return duct opening 204. The return duct opening 204 forms the end of an elongated air duct 206 having a first horizontal portion 208 defined in part by the top 102 of the refrigerator and a panel 210 suspended from the top 102. The elongated duct 206 has a second portion 212, which is vertical and located against or as part of the rear side 112. The first portion of the duct 208 and the second portion of the duct 212 are coupled to each other by a curving section 214, which also forms part of the elongated duct 206. In a preferred embodiment, the elongated duct 206 and its component portions are formed from a plastic panel having a width, which in FIG. 2 extends into the plane of the figure, equal to the interior width of the refrigerator 100.

Still referring to FIG. 2, warm air 202 drawn into the return duct opening 204 is also drawn through conventional evaporator coil 216, which absorbs heat and thus cools the air that flows through the evaporator 216. Movement of the air into the return duct opening 204 and the evaporator is responsive to a conventional fan 218 located “downstream” of the evaporator 216 in the first duct portion 208.

Air drawn through the evaporator 216 by the fan 218 is also forced by the fan 218 through the curving connecting portion 214 and into the second, vertical portion 212. The refrigerated air, identified by reference numeral 220, is forced downwardly toward the bottom 104 of the refrigerator 100. When the refrigerated air 220 reaches the bottom 104 of the second portion 212 of the duct 206, the air is forced into a converging duct portion 230 defined by an inclined and perforated screen 232. As described more fully below, air that is below the perforated screen 232 is at a pressure that is elevated, i.e., higher than, the pressure of the air above the screen 232.

The perforated inclined screen 232, which is also referred to interchangeably hereinafter as the screen 232, the inclined screen 232 and the perforated screen 232, has a downwardly-directed bend or inflection point 234 located near the door 110 whereat the perforated screen is directed to the bottom 104 of the refrigerator 100. The bend 234 extends across the width of the screen 232, which extends into the plane of FIG. 2. The bend meets the bottom 104 of the refrigerator 100 at a termination edge identified by reference numeral 236.

The inclined screen 232 has a rear edge 238 abutting and attached to the front panel 240 of the second portion 212 of the duct 206. The rear edge 238 also extends across the width of the screen 232. Since the front panel 240 of the second portion 212 of the duct 206 is effectively the rear or back side of the refrigerated air space, the front panel 240 is considered to be a rear side of the refrigerator to which the incline screen 232 is attached at its rear edge 238.

The inclined screen 232 is perforated with numerous holes 242. Air 220 that is forced down the second duct portion 212 enters the space below the screen 232. Since air continues to flow through the screen 232, the screen 232 is considered to act as a duct. Since the screen 232 is inclined at an inclination angle 250 as shown, and which is measure relative to the bottom 104 of the refrigerator 100, the screen 232 defines a converging air duct 244.

Cold air 220 exits the second portion 212 of the duct 206 at a relatively tall opening 213 having a height 246. The height 245 of the opening 254 is defined by the elevation of the rear edge 238 above the bottom 104 of the refrigerator 100. The screen 232, being inclined at an angle 250 relative to the bottom 104 converges or gets closer to the bottom 104 as the screen length extends toward the front 110 of the refrigerator 100. The inclination point or front edge 234 of the screen 232 is thus much closer to the bottom 104 than is the rear edge 238 of the screen. The converging duct portion 244 is thus considered to have an opening 254, into which cold air 220 from the second portion 212 of the duct 206 flows, responsive to the fan 218. In FIG. 2, the opening 254 portion of the converging duct portion 244 created by the screen 232 can be seen to be located or “open” just below the rear edge 238 of the inclined screen 232.

FIG. 3 is a perspective view of the refrigerator 100. The height of the refrigerator as shown in FIG. 3 appears to be less than the height of the refrigerator as depicted in FIG. 2.

The inclined screen 232 can be seen to extend all across the interior 200 of the refrigerator to meet and make contact with both the left side 106 and the right side 108. The front 110 can be seen to be a door 110, which is attached to the top 102 and the bottom 104 by hinges 300 that are attached at the right side 108 of the refrigerator. A handle 302 enables the door 110 to be opened and closed. A glass panel 304 in the door 110 allows the interior of the refrigerator to be viewed without opening the door.

As FIG. 3 is drawn, a first duct portion 308 is drawn with a warm air inlet 306 located near the front door 110 and that extends across the width 310. The warm inlet 306 is also depicted as being “open” or “facing” the door 110 whereas the warm air inlet 204 shown in FIG. 2 faces downwardly. The evaporator 216 and fan 218 shown in FIG. 2 are omitted from FIG. 3 for clarity.

The inclined screen 232 has a top surface 312 and a bottom surface 314. The holes 242 extend through the top and bottom surfaces 312 and 314 respectively. Air flows through the holes 242 by virtue of the fact that the air pressure inside the converging duct portion 244, below the screen 232 and its lower or bottom surface 314, is greater than or “elevated” relative to the pressure in the interior portion 200 of the refrigerator 100, i.e., above the top surface 312. Stated another way, a fan that draws air into the warm air inlet 306 and pressurizes the portion of the duct 206 that is downstream from the fan, also pressurizes the converging duct portion 244. The converging duct portion 244 and the inclined screen 232 thus define a pressurized air plenum. If the pressure drop across the screen 232, i.e., the pressure below the screen 232 minus the pressure above the screen, is substantially uniform across the area of the screen 232, the volumetric flow rate of air through each of the openings 242 through the screen 232 will also be substantially uniform. On the other hand, if the air pressure drop across the screen is not uniform, air flow through some of the holes 242 will be greater than or less than air flow through others holes 242. The pressure drop across the screen is kept relatively uniform across the lower surface 314 of the screen 232 by selecting one or more of: the fan's air flow rate; dimensions of the duct 206, including its various portions; the area of the screen 232; the inclination angle 250 of the screen 232; the number of holes 242; the open area of the holes 242 and the thickness of the material from which the screen 232 is made,

FIG. 4 is a front elevation view of the refrigerator 100. As with the depiction in FIG. 3, the screen 232 can be seen to extend all the way between the left side 106 and the right side 108 of the cabinet interior 200. The holes 242 can be seen to be uniformly distributed across the screen 232. Holes 242 can also be seen though the portion of the screen below the front edge 234. These holes are directed towards the door 110.

FIG. 5A is a left-side view of the refrigerator 100 but with an evaporator 516 shown as being located downstream from a fan 518, which draws warm air into a vertically oriented warm air inlet 504. FIG. 5A is thus an alternate embodiment. Refrigerated or cold air 220 is shown passing through the evaporator 616 into the pressurized plenum 254 which is defined by the converging duct portion 244 which is in turn defined by the inclined screen section 232. The refrigerated air 220 is depicted as passing through the screen 232 and upwardly through the interior 200. The rate at which refrigerated air 220 passes through each of the openings 242 is considered herein to be a volumetric flow rate. If the pressure across the bottom surface 314 of the screen 232 is uniform, and if the area of each opening 242 is the same or substantially the same, the volumetric flow rate through each of the openings 242 will also be substantially the same.

As used herein, a completely uniform flow rate or nearly uniform flow rate through the holes 242 in the screen 232, is considered herein to be a uniform air flow profile. In FIG. 5B, a uniform air flow profile is depicted using vectors 502, which extend upwardly from openings 242 in the x-z plane, the heights of which are uniform.

FIG. 6 is an isolated view of a portion of the screen 232 proximate to the front edge 234. In FIG. 7, the screen 232 can be seen to have a thickness 600. The holes 242 can be seen as themselves being ducts having lengths equal to the thickness 600 of the material from which the screen 232 is fabricated. Those of ordinary skill in the art will recognize that as the thickness 600 increases, head loss will increase accordingly, although not significantly relative to the losses associated with the sudden contraction then expansion of the flow path. The diameter 602 or the open area of the hole 242 and the thickness 600 of the screen 232 thus affect the volumetric flow rate of air through the screen and its holes.

Referring again to FIG. 5, the converging duct portion 244 itself acts as a duct to the cold air 220 forced into it by the fan. Keeping the volumetric flow rate uniform across the area of the screen is thus a function of the angle of inclination, flow rate of air into the duct portion 244 and the open area of each of the holes, including their number and spacing.

FIG. 7 is a perspective view of an alternate embodiment of a refrigerator 700 having an inclined screen 702. FIG. 8 is a front elevation view of the alternate embodiment.

The screen 702 has a width 704 less than the width 706 of the interior 708. The rear edge 710 meets or abuts with the rear surface 712 of a rear duct 714. The width 704 being less than the width 706 provides open spaces 716 beyond the left edge 718 and the right edge 720 of the screen 702. The open spaces 716 are considered herein to be themselves openings within a perimeter region 722 that is located beyond the extreme edges 718 and 720 of the screen 702. The perimeter 722 is located beyond the edges 718 and 720. The fact that there is no screen between the edges 718 and 720 and the left side 730 and the right side 732 means that air is able to freely flow upward through those openings providing an increased air flow there through.

FIG. 9 is a cross-sectional view of yet another embodiment of the refrigerator 900 but in FIG. 9, the screen 902, which is also inclined at an angle 904, does not extend back to front side 906 of a rearward-located duct 908. An opening 910 is instead located near the top or rear edge 1012, which allows refrigerated air 914 to flow readily into the interior volume 916 of the refrigerator cabinet 900.

Those of ordinary skill in the art will recognize that while the openings in the screens depicted and described above are substantially uniform, as well as being evenly spaced, alternate embodiments include the use of holes through a screen that are neither equal nor evenly distributed. Stated another way, in a preferred embodiment the thickness of the screen, its area, its extent between the left and right sides, the number of openings, the inclination angle of the screen are selected or configured to provide a uniform distribution of air flow through the screen across its area or substantially across the area. In one alternate embodiment, at least one of the thickness, the area and number of openings and the inclination angle are configured to provide a non-uniform air flow distribution. In one such alternate embodiment, at least one of the thickness, area and number of openings and the inclination angle are each configured to provide an increased air flow through at least some of the openings that are near at least one of the left edge of the screen, the right edge of the screen or the front edge in order to provide an increased air flow through such openings. The increased air flow through such openings is relative to an average air flow through at least a central region of the inclined screen portion.

In yet another alternate embodiment, at least one of the thickness, area, number of openings, inclination angle and the dimensions of the screen inclined portion between the front edge and the rear edge are selected to provide an increased air flow through openings in a region considered to be a perimeter that is around the exterior edges of the screen.

Those of ordinary skill in the art will recognize that the portion of the screen that is beyond the front edge (identified by “234” in the embodiment shown in FIG. 2) and which is directed downwardly to the bottom (“104” in the embodiment shown in FIG. 2) is at a different elevation angle relative to the bottom than is the screen portion (“232” in the embodiment shown in FIG. 2) between the front edge (“234” in the embodiment shown in FIG. 2) and the rear edge (“238” in the embodiment shown in FIG. 2). Those inclination angles are selected to imbue that front portion of the screen, i.e. the portion between the front edge 234 and the bottom 104 with the ability to increase air flow towards the door 110.

For purposes of clarity, it is important to note that the converging duct portion is considered to have an inlet. The inlet is considered to be at least a geometric plane extending downwardly from the rear edge (“238” in the embodiment shown in FIG. 2) to the bottom (“104” in the embodiment shown in FIG. 2) of the refrigerator and between the left side and the right side (“104” and “108” respectively in the embodiment shown in FIG. 2). The opening or inlet of that converging duct portion is thus coupled to the outlet of the second portion (“212” in the embodiment shown in FIG. 2) of the aforementioned elongated duct (“206”). The outlet of the second duct portion is preferably of the same shape and dimensions as the inlet to the converging duct portion.

In a preferred embodiment, which is shown in FIGS. 2 and 3, the inclined screen 232 is attached to supports that are themselves attached to the left side 104 and the right side 106. The duct between the converging duct portion and the warm air inlet 204 is preferably a unitary structure, however, in alternate embodiments they can be separate sections joined to each other by appropriate and well known prior art methods of connecting air ducts to each other.

The foregoing description is for purposes of illustration. The true scope of the invention is set forth in the following claims. 

What is claimed is:
 1. A refrigerator having an interior defined by first and second sides, a rear side, a front opening having a door, a top and a bottom, the refrigerator comprising: a first inclined screen portion located proximate to the bottom and between the first and second sides of the interior and between the rear side of the interior and the front opening, the first inclined screen portion having a front edge proximate the front opening and a rear edge proximate the rear side, the inclined screen portion having a first inclination angle, relative to horizontal defining a converging first duct portion, the first duct portion having a first height at the rear edge and a smaller second height at the front edge, the first duct portion having an opening at the rear edge; wherein the inclination angle and openings in the screen establish an air flow profile in the refrigerator cabinet.
 2. The refrigerator of claim 1, wherein the first inclined screen portion extends to first and second sides and extends to the rear side.
 3. The refrigerator of claim 1, wherein the screen is comprised of: a panel having a top surface and a bottom surface, a first thickness between the top and bottom surfaces, and a number of first openings, the number of openings having a first area and extending through the top and bottom surfaces; wherein, the number of first openings, the first thickness, the first area, and the first inclination angle being selected and configured to provide a distribution of air flow through the first inclined screen portion responsive to an input air stream at the duct opening.
 4. The refrigerator of claim 3, wherein the first openings are substantially uniformly spaced apart from each other.
 5. The refrigerator of claim 3, wherein the first openings are substantially uniformly sized.
 6. The refrigerator of claim 3, wherein the first openings are non-uniformly spaced apart from each other.
 7. The refrigerator of claim 3, wherein the first openings are non-uniformly sized.
 8. The refrigerator of claim 1, wherein the first thickness, first area and number of first openings and the first inclination angle are configured to provide a distribution of air flow through the first inclined screen portion that is substantially uniform across the area of the first inclined screen portion.
 9. The refrigerator of claim 1, wherein the first thickness, first area and number of first openings and the first inclination angle are configured to provide a non-uniform distribution of air flow through the first inclined screen portion.
 10. The refrigerator of claim 1, wherein the first thickness, first area and number of first openings and the first inclination angle are configured to provide an increased air flow through at least some of the openings proximate the front edge, to provide an increased air flow toward the door. relative to the air flow through a region of the first inclined screen portion.
 11. The refrigerator of claim 1, wherein the first thickness, first area and number of first openings and the first inclination angle and dimensions of the first inclined screen portion within a perimeter region are configured to provide an increased air flow through at least some of the openings that are within the perimeter region.
 12. The refrigerator claim 1, wherein the first inclined screen section is coupled to a second inclined section having a second inclination angle greater than the first inclination angle and extending downwardly from the front edge toward the bottom, the second inclined section being comprised of a second thickness and second openings having a second area.
 13. The refrigerator of claim 12, wherein the first and second thicknesses are substantially the same and wherein the first and second areas are substantially the same.
 14. The refrigerator of claim 12, wherein the first and second thicknesses, the first and second areas and the first and second inclination angles are configured to provide an increased air flow through at least some of the first and second openings proximate the front edge, to provide an increased air flow toward the door. relative to the air flow through a region of the first inclined section.
 15. The refrigerator of claim 1, wherein the first duct portion has an inlet with a first cross sectional area and is coupled to a second duct portion having an outlet coupled to the inlet of the first duct portion and having an inlet, the second duct portion being configured to provide an air stream at the outlet of the second duct portion that flows into the inlet of the first duct portion, the air stream provided to the inlet of the first duct portion having a substantially uniform air flow distribution over the cross sectional area of the inlet of the first duct portion.
 16. The refrigerator of claim 13, wherein the air stream has a direction through the first and second duct portions and wherein the direction and the cross sectional area are substantially orthogonal.
 17. The refrigerator of claim 14, wherein the second duct portion has a converging section located between the outlet and the inlet of the second duct portion, the inlet of the second portion being coupled to a fan, the converging section being configured to evenly distribute an air flow from the fan, substantially uniformly across the cross sectional area of the outlet of the second duct portion.
 18. The refrigerator of claim 13, wherein the first duct portion and the second duct portion are comprised of separate duct sections, joined to each other at the inlet of the first duct portion and the outlet of the second duct portion.
 19. The refrigerator of claim 13, wherein the inlet of the second duct portion is located proximate to the top of the refrigerator cabinet, whereby refrigerated air flows upwardly from the first inclined screen portion into the inlet of the second duct portion.
 20. A method of circulating air in a refrigerator cabinet having first and second sides, a rear side, a front opening having a door, a top and a bottom, the method comprising the steps of: forcing air into a plenum located proximate to the bottom of the refrigerated cabinet, the plenum defined by a bottom, upwardly extending sides, an air input port coupled to an air duct and an inclined panel extending between the upwardly extending sides and facing upwardly toward the top of the refrigerator cabinet, the inclined panel having a thickness and perforated with a plurality of openings distributed across the inclined top panel, each opening defining an open area in the inclined panel through which air from below the inclined panel can pass and flow upwardly in the refrigerator cabinet, the thickness of the top panel, the number, open area and spacing of the openings and a flow rate of air driven into the plenum creating a positive pressure below the inclined panel that is greater than the pressure outside the plenum such that air in the plenum below the inclined panel flows upwardly through the plurality of openings and upwardly through the refrigerator cabinet; collecting upwardly flowing air in the refrigerator cabinet at an inlet of a duct located near the top of the refrigerator cabinet; and routing air collected at the duct inlet through the duct to an evaporator and from the evaporator back into the plenum. 